From c0d48e341763ef07b65487b55960df8d9f13fb4f Mon Sep 17 00:00:00 2001
From: Svyatoslav Kuzmich <svyatoslav.kuzmich@jetbrains.com>
Date: Mon, 6 Sep 2021 18:18:15 +0300
Subject: [PATCH] [Wasm] Support external functions

---
 .../kotlin/backend/wasm/ir2wasm/BodyGenerator.kt      |  2 +-
 .../backend/wasm/ir2wasm/DeclarationGenerator.kt      | 11 ++++++-----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
index 3324195ecbe..e23e1e8e4cd 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
@@ -296,7 +296,7 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
 
         // Return types of imported functions cannot have concrete struct/array references.
         // Non-primitive return types are represented as eqref which need to be casted back to expected type on call site.
-        if (function.getWasmImportAnnotation() != null || function.getJsFunAnnotation() != null) {
+        if (function.getWasmImportAnnotation() != null || function.getJsFunAnnotation() != null || function.isExternal) {
             val resT = context.transformResultType(function.returnType)
             if (resT is WasmRefNullType) {
                 generateTypeRTT(function.returnType)
diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt
index 6358ae5d16b..b3b4834ce38 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt
@@ -49,7 +49,12 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
         if (declaration is IrConstructor && backendContext.inlineClassesUtils.isClassInlineLike(declaration.parentAsClass))
             return
 
-        val jsCode = declaration.getJsFunAnnotation()
+        val isIntrinsic = declaration.hasWasmNoOpCastAnnotation() || declaration.getWasmOpAnnotation() != null
+        if (isIntrinsic) {
+            return
+        }
+
+        val jsCode = declaration.getJsFunAnnotation() ?: if (declaration.isExternal) declaration.name.asString() else null
         val importedName = if (jsCode != null) {
             val jsCodeName = jsCodeName(declaration)
             context.addJsFun(jsCodeName, jsCode)
@@ -58,10 +63,6 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
             declaration.getWasmImportAnnotation()
         }
 
-        val isIntrinsic = declaration.hasWasmNoOpCastAnnotation() || declaration.getWasmOpAnnotation() != null
-        if (isIntrinsic) {
-            return
-        }
 
         if (declaration.isFakeOverride)
             return